BACKGROUND OF THE PRIOR ART
U.S. Pat. No. 3,471,548 describes compounds having the structural formula ##STR1## wherein R is chloro, bromo, fluoro or fluoromethyl. The compounds are known to cross the blood brain barrier and are known to have muscle relaxant properties and to be useful in the treatment in man of spasticity of spinal origin.
Neuroleptic drugs are used to treat schizophrenia. Examples of common neuroleptic drugs include phenothiazines such as chloropromazine; butyrophenones such as haloperidol and others such as pimocide and clozapine. Side effects of neuroleptic drugs include sedation and tardive dyskinesias. The latter side effect is particularly important because it results in involuntary muscle movements especially of the face and mouth which become irreversible. The onset of this side effect is directly related to the amounts of and length of time which a neuroleptic drug is used in treatment.